It is often desired or necessary for medical reasons to permanently close body vessels such as veins, arteries, body tubes, etc. Of particular utility is an ability to close the fallopian tubes of women for sterilization purposes.
One method for sterilization in females is surgical tubal ligation, a procedure in which the uterine tubules are tied and cut or clamped through an incision made through the wall of the abdomen. When done endoscopically, the pelvic cavity must be pneumatically inflated using an inert gas. Aside from injury due to over inflation, numerous cases of the formation of embolisms have been reported. Tubal ligation done with a laparotomy requires a surgical incision in the abdomen between 6 and 12 centimeters long done under general anesthesia. Aside from permanent scar formation at the site of incision, there are reported cases of death due to anesthesia complications.
Other methods for female sterilization have been investigated. In one technique, investigators have transcervically instilled the sclerosing agent quinacrine into the uterus and fallopian tubes to create a permanent closure of the fallopian tubes. Major drawbacks from this procedure are the need of repeat applications and a significant level of side effects.
Another technique involves transcervically injecting a curable elastomeric composition such as silicone into the fallopian tubes in an amount sufficient to fill the portion of the oviduct adjacent the uterus. The elastomeric composition is allowed to solidify to thereby nonsurgically block the tube. Erb, Method and Apparatus for No-Surgical, Reversible Sterilization of Females, U.S. Pat. No. 3,805,767 (Apr. 23, 1974). This technique is time consuming, however, and requires a high level of technical skill both for the preparation of the silicone and for performing the procedure.
Cohen, et al, Method for Tubal Electroligation, U.S. Pat. No. 5,556,396 (Sep. 17, 1996) discloses a method for tubal ligation by providing an electrically energizable electrode to a fallopian tube. The electrode is advanced into the fallopian tube and energized to thermally damage the fallopian tube, thereby causing enough scarring of the fallopian tube to permanently occlude it. The Cohen patent is hereby incorporated by reference.
Others have proposed placement of an occlusive wire or coil within the fallopian tubes to occlude them. Ton, Endoluminal Coil Delivery System having a mechanical release mechanism, U.S. Pat. No. 5,601,600 (Feb. 11, 1997), proposes placement of a Guglielmi detachable coil (typically used for vascular occlusion) deep within the fallopian tube, past the isthmus. The coil must be delivered into the fallopian tubes with a delivery catheter extending from the uterus into the fallopian tubes.
Many of the prior art sterilization methods require placement of an occluding object or device deep within the fallopian tube. Theoretically, the prior art devices make sense. However, the fallopian tubes have proven to be very difficult to cross with any useful device. In the typical human anatomy, catheters and guidewires cannot always navigate through the fallopian tubes as required by the methods of the prior art.